1. Field of the Invention
This invention relates to earphones of the type engaged with the user's ear and, more particularly, to an earphone of the type carried on the external flap, or lobe, of the ear, and which is adapted to improve the feel of fit on the ear and also to improve the transducer characteristics.
2. Description of the Prior Art
As the prior art transducer of the type engaged with the ear, there is one in which the body of a transducer is provided with an integral loop-shaped curved engagement section mounted on the outer surface of the body such that it extends in the direction of the sound radiating surface of the transducer. In this earphone, a ring-like thick pad is provided to project from the edge of the sound radiating surface of the transducer body.
When fitting the above earphone on the ear-lobe, the ear-lobe is inserted into an annular portion formed by the body and curved engagement section, whereby the earphone is held on the ear-lobe by the retaining force produced by the elastic deformation of the ear-lobe and elastic deformation of the pad and also the retaining force produced by the engagement between the curved engagement section and ear-lobe that results from the insertion of the ear-lobe into the annular portion.
With the earphone of that type engaged on the ear, however, the shape and size of the curved engagement section are fixed, so that the readiness of the insertion of the ear-lobe varies with the user, and it is likely that the ear-lobe is excessively tight or there may be a feel that the earphone may fall off. Further, since the height of the ear hole with respect to the ear-lobe varies with the user, it is likely that the sound radiating surface fails to be correctly positioned with respect to the ear hole, that is, it may fail to be located at the optimum sound collection position. Further, the angle of the ear-lobe with respect to the side of the head varies with the user, so that it is likely that a force tending to crush part of the ear-lobe is generated and that the sound radiating surface is not uniformly set with respect to the hear hole, thus spoiling the sound quality.
There is also a different type of prior art earphone of the type engaged on the ear, in which the engagement section is constituted by an arcuate rod-like spring. This earphone is superior to the aforementioned earphone having the loop-shaped engagement section in respect of the readiness of fitting on the ear-lobe. However, the state in which the earphone is fitted on the ear-lobe is not so stable as with the first-mentioned earphone, and therefore deterioration of the sound quality in common. Further, since the position of mounting of the curved lever section with respect to the base is fixed in spite of the fact that the position of the ear hole with respect to the entire ear-lobe varies with the user, it is difficult to locate the sound radiating surface in the optimum sound collection position with respect to the ear hole. Further, since the mounting position is fixed, as mentioned earlier, in spite of the fact that angle of the ear-lobe with respect to the side of the head varies with the user, when the curved engagement section is fitted on the ear-lobe, the ear-lobe is liable to be partly crushed. In such a case, the sound radiating surface cannot be uniformly fitted with respect to the ear hole, thus spoiling the sound quality.
As a further variety of prior art earphone of the type engaged on the ear, there is one in which a base is provided on the outer side surface of the transducer body and one end of a curved lever section which is made of a flexible rod member and has arcuate shape is mounted on the base. In this earphone, a ring-like thick pad is mounted on the edge of the sound radiating surface of the front of the transducer body. When fitting this earphone on the ear-lobe, the ear-lobe is inserted into the space between the transducer body and curved lever section, whereby the earphone is fitted on the ear-lobe such that the ear-lobe is clamped between the transducer body and curved lever section by the spring force of the curved lever section.